Category Archives: Linux

Setting Different Prompt for Different Konsoles

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Once in a every while I get an itch to tweak my desktop, in my latest tweaking session, I ended up customizing my terminal (bash) prompt and wanting different prompts for different Konsoles (KDE terminal applcication) profiles.

First one is easy, you can lots of posts for that, you can even do it in mac osx, but problem is, changing value for PS1 in .bashrc, effects all terminal windows, and there is no obvious way to set-up different prompt for different profiles in Konsole. But after searching for a while, I finally figured out how to do it, thanks to #kde on freenode.net.

In General tab of Profile configuration there is a button to set Environment variables. These values are read before .bashrc, so setting PS1 here has no effect, so what we can do, is set another random variable here, and then in .bashrc check if the variable is set or not, in either case we can set the value of PS1 accordingly. For instance, I have set

AlternateKonsolePrompt=1

in Environment and here is the code from my .bashrc:

 
PS1='[\u@\h \W]\$ '

if [ -n "$AlternateKonsolePrompt" ]; then

    PS1='\w \$ '

fi
 

 

Where the first PS1 is the default prompt, and the second one is for my profile.

Docky – Dock Bar For Linux

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After searching for a long time for a good, beautiful, easy to configure dock for Linux that can also work without compositing effects, I had finally given up, when I found out that Gnome-Do, my favorite application launcher, is going to feature a dock in it’s next release. Today, I downloaded and installed PPA packages for Ubuntu and gave Gnome Do’s docky a try.

docky

Docky is basically a special theme of Gnome-do, to access it, you have to go in Gnome-Do Preferences -> Appearance and change it’s Theme to docky. As soon as you select docky, you will notice a huge dock bar appear at the bottom of your screen. By default it shows your most used applications. If you don’t like it’s size, just take your mouse pointer to it’s vertical border and it will change into resize pointer, you can then drag it away from screen border to increase the size, and towards the screen border to decrease the size.

Adding and removing icons from dock is as easy as dragging an item on the dock or dragging it away, depending on you are adding or removing. Another way to add applications to dock is search for them using Gnome-Do and press the small plus sign below it. You can also right click and remove applications from it.

Docky also replaces usual task bar, though it is bit lacking in this front for now, but it is to be expected, as it’s still alpha quality. Currently, docky doesn’t provide a way to access different windows of same application, that is, even if you have 6 firefox windows open, it will show them as one.

Docky can use all plugins for Gnome-do, though there aren’t any docky specific plugins available yet (like start menu, time, systray etc.), but I am sure community will start contributing soon enough. If you are looking for a nice dock yourself, give it a try, though beware it’s still in it’s alpha quality so you might experience some crashes or unexpected behaviour, if that’s the case you should wait for it’s final release.

Read more about docky at it’s gnome do wiki.

Edit File in OpenOffice.org

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One of the great thing about Office software is, no matter how much you know about it, you can almost always find a feature you never knew existed. I am using OpenOffice.org for a very long time now (more than couple of years), though as my usage for office applications is quite low, I can be considered an average user for these applications.

Yesterday, while preparing for my exam, I was reading my handouts in OpenOffice Writer, when I noticed an “Edit File” button in toolbar, which I had never noticed before (though according to the screenshots I can see on web, it has been present since always). The button is used to switch between Edit and Read-only mode. If you are only reading a document and don’t want to edit it, switching to Read-only mode makes the experience more pleasent by removing formatting toolbars and improving overall page view.

Read-only Mode

Read-only Mode

Edit Mode

Edit file button can also be used to open a copy for editing, if you don’t have permissions to edit the file you are currently reading.

It’s not some huge feature, but if you read many documents / ebooks in OpenOffice.org, or want to edit a read-only file, it can be quite useful, and the fact that I (and few other people I know) didn’t know about such a simple feature made me write about it. It’s interesting how many people don’t know about most of the features present in such huge software. If you know any such feature which no one else seems to know, do share it with us! :)

Piwik + Adobe AIR = Open Source Desktop Web Analytics

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My favourite web analytics software Piwik just got desktop integration.

For those who haven’t heard of Piwik before, it’s open source web analytics software which you can host on your own server. It is still in beta, but I am using it for few months now and haven’t faced any problem. You can try it out using the online demo on their site.

According to Piwik blog, two desktop applications for Piwik are now available, made by piwik users. One of them, Piwik Connector is a simple app that shows hourly visits on all your Piwik websites, it would be useful for people who track many sites and don’t want too much stats.

For power users, Desktop Web Analytics provides much more advanced view, it brings all piwik stats to your desktop. Both these software are still early in development, so, you might face couple of problems, for instance, I wasn’t even able to save my profile in Desktop Web Analytics, but the good thing is work is being done on it.

P.S: Forgot to mention, both these apps are developed in Adobe AIR, which means they are available on Linux, Mac & Windows.

TweetDeck – Reducing Twitter Information Overload

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Yesterday I found out about new Adobe AIR Twitter client, TweetDeck, finally an application that makes it possible to cope up with information overload on twitter.

TweetDeck has multi-column view, it’s first column display all latest tweets (like “home” on twitter.com). Other columns can contain replies, direct messages, groups (tweets from selected people), searches and latest twitscoop. Of course if you like traditional twitter clients, you can close these other columns, but then you will not be using it’s full potential.

TweetDeck also features a “timeframe” feature, which allows user to filter tweets by time since posted, from last 1 hour to 48 hours, this can be very useful in filtering already read tweets and eliminating noise. All tweets are stored on local database, which also allows user to browse them while offline, any tweet posted or DM posted in that time are posted when back online.

TweetDeck is currently a beta, and even though it’s version is 0.18, it’s very functional and I haven’t encountered any bug yet. So, if you, like me have been overwhelmed by too much information on twitter and want to ease the load, give TweetDeck a try.

Now all that is remaining is to find a good feed aggregator!

Urban Terror – First Person Shooter

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Since I have switched completely to linux, I am always on the look out for native linux games. A genre that is very easily available on linux is First Person Shooters. There are many good quality multiplayer FPS games available on linux, most of these are based on Quake 3 engine, resulting in very good quality even on little older machines.

Even though I used to think all these FPS games are similar to each, they offer very different game play from each other, so, I started the quest to try all of them out. Let’s start with my favorite (for now):

Urban Terror:

Urban Terror is a modern reality based multiplayer FPS. According to their homepage:

Urban Terror can be described as a Hollywood tactical shooter; somewhat realism based, but the motto is “fun over realism”. This results in a very unique, enjoyable and addictive game.

In game, everyone carries knife and handgun (Beretta or Desert Eagle), other than that, you have 6 available inventory slots, 2 for weapons, 1 for grenades and 3 for other accessories (Kevlar vest, helmet, silencer, laser sight, med-pack, extra ammo etc.), out of these 6, you can only use 4 at one time, so, you should choose the weapons/accessories which suits your style of playing and current scenario. Health system also has a touch of reality to it, once you get shot that part of the body starts bleeding, and loses health until you (or your teammate) bandages it. Stamina depends on remaining health, so, if you are low on health, you might not be able to sprint much.

Urban Terror offers different game modes, including Bomb (Red team plants bomb at one of two pre-defined position, blue team has to defend those by either defusing bomb or killing all members of Red team) Free For All (FFA – Shoot everyone, the one with most frags win), Catch the Flag (CTF – Catch other teams flag and take it to your flag to score a point), Catch and Hold (C&H – map has many flags, touch one to change it to your color, you get a point for every minute you hold a flag), Team Deathmatch (TDM – Kill member of other team, the team with more score wins) & Team Survivor (TS – Same as TDM but once kill, you don’t re-spawn till the end of the round). You can read more about these in Urban Terror manual.

Urban Terror is a standalone Quake III Arena mod, though if you already have Quake III Arena, you can just install it as it’s mod, it is available on Linux, Macintosh & Windows. Image is taken from screenshots section on UrbanTerror.net

Atheros AR5007EG on Linux

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Update 2008-09-26: Fixed the link to madwifi package.

In my previous post about Sony Vaio’s hardware compatibility with Linux, I linked to ubuntuforums for a howto of installing Atheros AR5007EG wireless driver. Apparently it is not available any longer, so, I am posting the steps that worked for me.

Note: This howto is for 32bit systems, for 64bit, check this post on ubuntuforums.

First configure the system for compiling madwifi driver (these steps are ubuntu specific).

  1. Make sure restricted drivers are disabled by unchecking atheros drivers from System -> Administration -> Hardware Drivers
  2. Install necessary packages for compiling, if you don’t have them already. From terminal:
    sudo apt-get update && sudo apt-get install build-essential

Now, to actual installation of the driver. These steps should work on any distro, just open the terminal and enter those commands.

  1. Get latest snapshot of madwifi from http://snapshot.madwifi.org
    <span style="text-decoration: line-through;">wget -c http://snapshots.madwifi.org/special/madwifi-ng-r3366+ar5007.tar.gz</span>
    wget -c http://snapshots.madwifi.org/madwifi-hal-0.10.5.6-current.tar.gz
  2. Untar the downloaded file
    tar zxvf madwifi-hal-0.10.5.6-current.tar.gz
  3. cd into directory and compile the driver (directory name might be different for you)
    cd madwifi-hal-0.10.5.6-current
    make &amp;&amp; sudo make install
  4. Load the modules
    modprobe ath_pci

You should now be able to view and connect to wireless connections now. If it works fine add “ath_pci” (without quotes) in /etc/modules, so that you don’t have to manually load these files on every boot.

Linux File System – Part 2

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Let’s continue where I left my previous post on Linux file system, with information on different file systems commonly present in most distributions and small comparison between them.

ext2:

ext2 (or second extended file system) is the oldest file system for Linux still in use, and until recently one of the most famous. It was created to overcome the limitations of original ext file system (first file system for Linux).

ext2 is not a journaling file system and is not used by desktop users these days, but it’s still one of the most compatible and tested file system for Linux present.

ext3:

ext3 is the successor of ext2 and allows in-place upgrade from ext2. Main difference between the two is addition of journaling in ext3. As ext3 is basically just ext2 with some additional features, it can also be mounted as ext2, though doing so removes the advantage of ext3 file system. In other words, ext3 is backward-compatible. It also provides great compatibility with other operating systems, like windows, that is, you can mount ext3 (and ext2) partitions in Windows using utility.

ext3 provides three different level of journaling:

  • Journal
  • Ordered
  • Writeback

With “journal” offering maximum journaling (both meta-data and user-data), and “writeback” offering minimal journaling (only meta-data). Default journaling level is “ordered”, which is meta-data only journaling but which makes sure that data is written to disk before committing to journal (a precaution not taken in “writeback”), which save from data-corruption.

ReiserFS:

ResiserFS is also a journaled file system, but unlike ext3 it provides only meta-data journaling. It was introduced before ext3 and is the first journaling file system for Linux, though ext3, JFS and XFS very soon followed.

Even though ReiserFS is much faster than ext3, it is sometimes not preferred over other file systems. One of that reason was given by SUSE, when they changed their default file system from ReiserFS to ext3. According to them, ReiserFS doesn’t scale very well on multiple core systems as the critical sections are executed on only one core at a time.

Work on it’s successor Reiser4 is going on, and it has been announced that no new features will be added in ReiserFS. And as Reiser4 won’t feature in-place upgrade from ReiserFS (meaning all data will be lost on partition when upgrading), it has also turned down some ReiserFS users.

XFS:

XFS is another journaling file system and like ReiserFS, it only supports meta-data journaling. It is one of the oldest journaling file system for UNIX, which was later ported to Linux.

On average XFS’ performance is not much different from ReiserFS, though where ReiserFS’ provides great speed when dealing with smaller files, XFS is much better with large files.

Like all other file systems, XFS has it’s own disadvantages too, deleting files is slower than other file systems, and creating/deleting directories also takes more time. XFS also has no un-delete utility, which makes it almost impossible to recover any data once it is deleted (there appears to be one way to do it, if you are desperate enough). Also XFS file system can not be shrunk (it’s size can be increased though).

There is no utility to mount XFS file system under windows. There used to be crossmeta drivers that allowed read/write support in windows, but it isn’t available anymore, even when it was available, it was supposed to be quite buggy.

JFS:

JFS (Journaling File System) is one of the lesser known file system. Like XFS it has been around quite some and then later ported to linux. It offers meta-data journaling, similar to that of XFS and ext3′s “writeback”.

I haven’t tried JFS yet, but according to reviews and others I have checked with, it provides good speed and reliability. Also, it works efficiently even under high load, and doesn’t use too much CPU in these cases, which makes it preferred file system in cases when CPU efficiency is required, though it is not as widely supported by Linux distributions as the other file systems mentioned here.

I couldn’t find any utility or information to mount JFS under windows, most probably there isn’t one.

Conclusion:

All file systems have different advantages and disadvantages and is useful in particular scenario. ext2 is best to use when installing Linux on flash disk. ext3 provides better data recovery option than other file systems so, it’s preferred to use it for /boot or / (root). Either ext3 or ReiserFS can be used to share partition with windows installtion on same computer. XFS is good to use for large parition which contains large files, like movie collection, backup data etc. Whereas JFS can be used pretty much anywhere, preferablly on partition which contains both large and small files and when that system doesn’t dual-boot with windows.

Linux File Systems

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File system is a system to store and access the files (and directories) on any computer. Usually users don’t have to worry about which file system they are using, operating systems take care of it all. Though knowing their strength and weaknesses can sometimes help one to choose better option depending on the scenario.

There are many file systems present, suitable for different needs and can be categorized in many different categories, though we aren’t going to discuss them all here (if you are interested, you can check the list of all file system). In most Linux distributions, there is option to choose from two to five different file systems, which can be classified in two general categories:

  • Journaled (or journaling) File System
  • Non-journaled File System

Journaling File System:

Journaling file systems makes a log (or journal) of all the changes made before they are written to disk. This is helpful when system crash or power failure may cause loss of some data, while the changes are still being written to disk. In such case, system compares the disk state with journal, and update the disk where required, resulting in data recovery.

Every file has two parts, data and meta data. Data (or user data) is everything present in the file, that is, in case of text file it will be all the text present in file, for music file, it will be the music etc. whereas, meta data is data about data, like when was file last accessed, modified or created. Title of the song and artist information for music file and author information stored by some office programs is also meta-data.

This brings us to a sub-category of journaled file system.

  • Meta-data Journaling

As the name implies, meta data journaling file systems only log the meta data of the file and not the user data. It provides better performance then complete journaling file system, but doesn’t provide full data recovery options.

Non-journaled File System:

Non-journaled file system are those which doesn’t provide journaling. Which means in case of system crash or power failure, there are chances of data getting corrupt. It also means data is written just once (as it doesn’t have to written to the journal) there are fewer read/write operations on disk compared to journaled file system, which makes it preferable to use on flash drives and other solid-state drives, which can increase their life span.

That’s all for now, in next post I will provide comparison of different file systems for linux.

Linux on Acer Aspire 5720

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Due to some personal problems, I had to swap my notebook (Sony VAIO) with my brother’s (Acer Aspire 5720, also known as TravelMate 5720), for a month. So, like any honorable linux geek, I didn’t waste any time and installed linux – Ubuntu 8.04 – on it.

Hardware:

  • VGA: Intel X3100
  • Audio: Intel 82801H HDA (ICH8 Family), builtin microphone
  • Modem: Conexant
  • Ethernet: Broadcom NetLink BCM5787M Gigabit Ethernet
  • Wireless: Intel PRO/Wireless 3945abg Network Connection
  • Special Keys: FN keys, volume control, hotkeys (wireless, bluetooth & two editable keys), euro sign, dollar sign
  • Misc: Card Reader, Bluetooth, InfraRed

What Works:

I really love it when everything just works, and with Aspire 5720, everything really does, well atleast all the important stuff anyway. VGA, audio, ethernet, FN keys, volume control, wireless, bluetooth and power saving options (hibernate and suspend) works out of the box.

What Doesn’t Work:

  • Modem: Unfortunately, soft-modems are still a weak point for linux, though, fewer and fewer people use dialup connections now, so, it’s not much of a problem. If you really want a driver, you can get it from linuxant.com, for a suitable price ofcourse.
  • Programmable Hot keys: These hot keys don’t work out of the box, and I couldn’t find any way to make them work in my quick google search.

Couldn’t Try Completely:

  • Wireless: Intel PRO/Wireless 3945abg is fully supported in linux, and according to many reports works out of the box in ubuntu but I wasn’t able to check that because my wireless router is out of order.
  • InfraRed: I don’t have any infrared device, so, didn’t check it either.

Conclusion:

I don’t have vast experience with notebooks, I have only tried a few, but out of these all Acer Aspire 5720 offers most hardware compatibility with linux. So, if you are looking for a nice laptop to use with linux, I would definately vote for this machine.